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Shrink hiberfil.sys with the Reduced Hibernate Type

Cut the hibernation file to about 40% of your RAM with powercfg /hibernate /type reduced — reclaim SSD space without losing hibernate.

WindowspowercfgdiskPower & SleepMedium risk
Run powercfg /hibernate /type reduced in an admin Command Prompt; restore the full file with powercfg /hibernate /type full.

01Command

Command
$ powercfg /hibernate /type reduced

02What it does

The hibernation file hiberfil.sys is normally sized to hold a full snapshot of your RAM — on a 32 GB machine that's a large chunk of the SSD. The reduced hibernate type keeps hibernate working but stores a partial snapshot, sizing the file to roughly 40% of installed RAM. The trade-off is that Fast Startup stops working, since it needs the full file. If you never use hibernate at all, powercfg /hibernate off removes the file completely instead.

03Risk

RiskMedium risk
RequirementsRun Command Prompt as administrator. Hibernate must already be enabled (powercfg /hibernate on).
!Warning: Switching the type deletes and recreates hiberfil.sys, so the current hibernation state is discarded — hibernate or shut down first. On very small RAM systems the reduced file can be too small to hibernate successfully.

04Undo

Undo
$ powercfg /hibernate /type full

05Sources

  • powercfg - SS64
    SS64 · technical · 2026-09-17
    Evidence: Reference for powercfg /hibernate options including /type full|reduced and the /size percentage.
  • powercfg Command-Line Options
    Microsoft Learn · vendor-doc · 2026-09-17
    Evidence: Documents powercfg /hibernate /type with values full and reduced — reduced creates a smaller hiberfil (~40% of RAM) supporting only hibernate, not Fast Startup.

Last verified: 2026-09-18 · Category: System & Settings

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